WordPress at a glance
function is not described

signup_nonce_fields() WP 3.0.0

Add a nonce field to the signup page.

No Hooks.

Return

Nothing (null).

Usage

signup_nonce_fields();

Code of signup nonce fields: wp-includes/ms-functions.php VER 5.1.1

<?php
function signup_nonce_fields() {
	$id = mt_rand();
	echo "<input type='hidden' name='signup_form_id' value='{$id}' />";
	wp_nonce_field( 'signup_form_' . $id, '_signup_form', false );
}